Atomic structure and the periodic table

Question 1

Define the term atom

Answer 1

The smallest part of an element that can exist. It has no electrical charge and is made up of a nucleus containing particles which are protons and neutrons as well as electrons in energy levels.
Measured in nanometers

Question 2

Define the term proton

Answer 2

A positively charged particle found in the nucleus of an atom

Question 3

Define the term neutron

Answer 3

A neutral particle found in the nucleus of an atom

Question 4

Define the term electron

Answer 4

A negatively charged particle which are found in energy levels (Shells) around the nucleus of an atom

Question 5

What is a nanometer

Answer 5

1 x 10 to the power -9 metres

Question 6

What is the atomic number of an element

Answer 6

It is the number of protons contained in the nucleus of an element

Question 7

What is the mass number of an element

Answer 7

It is the combined number of protons and neutrons contained in the nucleus of an element

Question 8

What is an isotope?

Answer 8

An isotope is an atom with the same number of protons but a different number of neutrons
eg carbon exists as C12, C13 and C14
they all have 6 protons but have 6,7 and 8 neutrons respectively.

Question 9

What is an ion?

Answer 9

It is a particle which has an electric charge because it does not have the same number of protons and electrons
eg CL- which has one more electron than protons and Mg2+ which has two more protons than electrons.
TIP - there is a direct relationship between the ionic structure of an element and its position on the periodic table.

Question 10

Describe the gold foil experiment carried out by Geiger and Marsden in 1909

Answer 10

They directed a beam of alpha (He2+) particles which travel very quickly through a thin sheet of gold . They expected all of the particles to pass through but a small number were deflected and bounced back.

Question 11

How did Rutherford explain the results of the gold foil experiment

Answer 11

He suggested that the deflection of the alpha particle was due to an electrostatic charge between the particle and a very small charged nucleus, he also said the nucleus could be massive.. He said that the nucleus may be either positively or negatively charged. A positive charged nucleus would deflect the positively charged alpha particle away whereas a negatively charged one would pull the particle toward and around it.

Question 12

How is the gold foil experiment explained nowadays.

Answer 12

The diameter of the nucleus of an atom is tiny in comparison to the atom 1:20000. The nucleus is positively charged. Most of the alpha particles pass through the gold atom. A few hit the nucleus and were deflected back as the positive charges repelled each other. Some came near the nucleus and were deflected slightly. .

Question 13

Who suggested the plum pudding model for the atom after discovering electrons and when was that?

Answer 13

J J Thompson in 1897.

Question 14

What did James Chadwick discover in 1932

Answer 14

That there are neutrons in the nucleus of an atom.

Question 15

Who suggested that electrons orbit the nucleus at specific distances in 1913?

Answer 15

Neils Bohr

Question 16

What is the name for a substance which is made from only one type of atom

Answer 16

element

Question 17

What is meant by the term relative atomic mass?

Answer 17

It is the average mass of all of the isotopes of an element.

Question 18

What are the four parts of each box on the periodic table in the correct order

Answer 18

1. relative atomic mass
2. Symbol
3. Name
4. Atomic number.

Question 19

Describe the properties of a metal

Answer 19

1. High melting and boiling points
2. Electrical and thermal conductor
3. High density
4. Malleable- can be hammered into shape
5. Ductile- can be drawn into a wire
6. Form positive ions in ionic compounds
7. Usually shiny in appearance.

Question 20

Describe the properties of a non metal

Answer 20

1. Low melting and boiling points
2. Not an electrical or thermal conductor- except graphite
3. Low density
4. Not malleable- brittle so cannot be hammered into shape
5. Not ductile- cannot be drawn into a wire
6. Form negative ions in ionic compounds
7. Usually not shiny (dull) in appearance

Question 21

Some elements are quite difficult to classify as either metal or non metal as they have characteristics of both, name two

Answer 21

Boron
Silicon
Germanium

Question 22

How are elements placed in the periodic table?

Answer 22

It depends on how many protons they have eg in increasing atomic number

Question 23

The periodic table has rows and columns but they are called by alternative names, what are they?

Answer 23

Rows = periods
Columns = groups

Question 24

What is a compound?

Answer 24

A substance which is made from 2 or more different elements which are chemically bonded.

Question 25

What characteristic is shared by all of the elements in a group?

Answer 25

They all have the same number of electrons in their outer shell.

Question 26

What are the names given to all of the elements in the first column of the periodic table?

Answer 26

The group 1 or alkali metals

Question 27

What are the main characteristics of the alkali metals

Answer 27

1. They all form ions with one more proton so +1 eg Li+
2. They all have one electron in their outer shell which they can lose easily- therefore
3. They are all very reactive and are stored in oil to stop them reacting with water and oxygen in the air
4. They are all soft and can be cut with a knife